Lower limb sagittal kinematic and kinetic modeling of very slow walking for gait trajectory scaling

PLoS ONE, 2018 · DOI: https://doi.org/10.1371/journal.pone.0203934 · Published: September 17, 2018

Simple Explanation

Lower extremity powered exoskeletons (LEPE) are an emerging technology that assists people with lower-limb paralysis. LEPE for people with complete spinal cord injury walk at very slow speeds, below 0.5m/s. An improved understanding of how able-bodied people biomechanically adapt to very slow walking will provide LEPE developers with more accurate models to predict and scale LEPE gait trajectories.

Study Duration

Not specified

Participants

30 able-bodied adults

Evidence Level

Not specified

Key Findings

1
Quadratic models based on walking speed had the strongest correlations with sagittal kinematic and kinetic gait parameters, with kinetic parameters having the better results.
2
The lack of a consistent inflection point indicated that the kinematic and kinetic gait strategy did not change at very slow gait speeds.
3
Gait speed had stronger correlations than stride-length and cadence for 18 of 33 parameters.

Research Summary

This research showed that peak sagittal kinematic and kinetic gait parameters, between 0.2 and 0.8 m/s, had a strong non-linear association with speed. The lack of a consistent inflection point indicated that the gait kinematic and kinetic strategy did not change at very slow gait speeds. The regression equations defined in this research should provide better results when modeling LEPE joint trajectories at very slow walking speeds.

Practical Implications

Improved LEPE Design

The equations derived from very slow gait speeds can improve modelling accuracy of peak sagittal gait parameters for gait trajectory scaling and LEPE development.

Enhanced LEPE Function

Appropriately scaled trajectories may enhance LEPE function, making it easier for users to complete steps successfully, enhancing mobility, balance, cadence, and walking speed of people with complete lower limb paralysis.

Clinical Decision Making

If data from this studies is used for clinical decision making on overground walking, the potential for less variability in the treadmill data should be considered.

Study Limitations

1
The main limitation to this study was how to control walking speeds.
2
Treadmill use may have influenced gait parameters by shortening stride length and cadence, increasing knee extension and forward trunk lean through stance, and increasing hip and knee flexion through swing
3
These equations should be tested on a separate dataset, within the same gait speed range

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